Human Performance in Flight Operations Error Management


With the achieved high reliability of modern aircraft systems, human performance has become a key focus area for flight safety. Various types of human error are often quoted as contributing factors to incidents and accidents. Safety officers at airlines observe human errors and even violations when they monitor the safety performance of their airline through safety reports and Flight Data Monitoring. Information or training alone cannot immunize a person or an organization against error. Improvement is only achieved through concrete improvements that make errors less probable and their consequences less severe.

The objectives of this Flight Operations Briefing Note are

  • To familiarize the reader with the key concepts of human error and violation.
  • To guide the reader towards productive solutions in error and violation management.

The perspective of this Briefing Note is at the organizational level. In other words, the aim is to help Safety Managers, Training Managers and other similar people to apply the most effective systemic solutions for managing errors and violations in their organization. Even if the Briefing Note certainly gives ideas for Error Management also at the individual level, it is not the primary aim here to give pilots new Threat and Error Management techniques, but rather to try reduce the number and gravity of Threats they face in the operation.

Defining Human Error and Violation

Errors and Violations

In everyday language, the term “error” is used in a very broad sense. For a more detailed discussion of the topic, more precise definitions are needed. The classification used here is in line with James Reason’s definitions.

Errors are unintentional (in)actions, which fail to achieve their intended outcomes.

Errors can only be associated with actions with a clear intention to achieve a specific intended outcome. Therefore, uncontrolled movements, e.g. reflexes are not considered errors. The error itself by definition is not intentional, but the original planned action has to be intentional. Furthermore, it is assumed in the above definition that the outcome is not determined by factors outside the control of the actor.

Violations are intentional (in)actions, which violate known rules, procedures or norms.

The fundamental difference between errors and violations is that violations are deliberate, whereas errors are not. In other words, committing a violation is a conscious decision, whereas errors occur irrespective of one’s will to avoid them. Cases of intentional sabotage and theoretical cases of unintentional violation (breaking a rule because the person is not aware of the rule) are outside the scope of this Flight Operations Briefing Note. Therefore, it is important to realize that within the scope of our discussion a person committing a violation does not intend the dramatic negative consequences which sometimes follow a violation - usually it is belived bona fide that the situation remains under control despite the violation. It is worth noting that many sources, even in the domain of aviation safety, use the term “error” in a wider sense, covering both errors (as defined here) and violations.

Errors can further be divided into the two following categories

  • Slips and lapses are failures in the execution of the intended action.

Slips are actions that do not go as planned, while lapses are memory failures. For example, operating the flap lever instead of the (intended) gear lever is a slip. Forgetting a checklist item is a lapse.
Mistakes are failures in the plan of action. Even if execution of the plan was correct, it would not be possible to achieve the intended outcome. Plans that lead to mistakes can be deficient (not good for anything), inappropriate good plans (good for another situation), clumsy (with side-effects) or dangerous (with increased risks).

Error Management

People in management positions often find it difficult to deal with human errors. Simple reactions like asking people to be “more careful” very rarely bring any improvement. The seemingly easy solution to add warnings in documentation usually turns out to have a very limited effect. Another natural reaction is to try to train people more, hoping errors would then be avoided. Whereas different technical and non-technical skills can be improved by training, therefore having a positive impact on certain types of mistakes, training does very little in preventing slips and lapses.
Therefore, one must accept the fact that errors cannot be completely prevented no matter how much people are trained and how many warnings are put in the operational documentation. The first step in successful error management is to understand the nature of the experienced errors and the mechanisms behind them. Real solutions for human error require systemic improvements in the operation. One way consists of improving working conditions, procedures, and knowledge, in order to reduce the likelihood of error and to improve error detection. Another way is to build more error tolerance into the system, i.e. limit the consequences of errors. Achieving such systemic solutions requires first adopting an organizational focus to error management, instead of focusing on the individuals committing the errors. Preventing errors is usually not possible. Therefore the correct term to use is Error Management. This chapter focuses first on the known error management strategies in general, and then goes on to discuss the specifics of managing slips, lapses and mistakes.

Violation Management

In simple terms, violation management consists of understanding the reasons for violations and then trying to remove these reasons. In an ideal situation, the organization facilitates learning from difficulties in the operations, and fixing them before people need to “fill the gaps” by violating. There are known factors that increase the probability of committing violations: Expectation that rules will have to be bent to get the work done, Powerfulness: Feeling that skills and experience justify deviating from the standard procedures, Opportunities for short cuts and other ways of doing things in a seemingly better way, Poor planning and preparation, putting the person in situations where it is necessary to improvise and solve problems “on the fly” as they arise. This set of factors is sometimes called “the lethal cocktail”. Often the conditions that induce violations are created, because the organization cannot adapt fast enough to new circumstances. The violator may be a very motivated person, trying to do things “better” for the company. This explains why management pilots are often more likely to violate, especially in small companies where business pressures are strongly felt due to very limited operational flexibility.

As with errors, it is important to look for the root causes of violations in the organization. Therefore, the solutions must also be implemented at that level. This also explains why violations are not necessarily always punishable. It is in no way the intention to undermine the importance of individual responsibility for one’s own actions. Dangerous and reckless behavior should never be tolerated. However, some routine or situational violations may have been imposed on the individual by deficient organization or planning, and any individual put in the same situation might find it difficult not to violate. Acceptance of a non-compliant way of doing the job may have become part of the local working culture, which also means that the whole group – including management - is responsible for the violation, not only the individual actually carrying it out. The ultimate goal is to establish a working culture, where violations are not an acceptable option. Like all cultural issues, this can take considerable time and effort. Chances for success are greatly enhanced if the employees themselves are involved in setting the limits of what is acceptable in their own work. The limits must then be clearly communicated and imposed.

Summary of Key Points

Errors and violations are more common in flight operations than one would expect. They have the potential to affect safety, although usually the robustness of the aviation system is high enough to contain errors and violations without significant consequences. The first step in error and violation management is to understand the mechanics behind them. This Flight Operations Briefing Note has aimed at providing the basic information on the subject. Successful management of errors and violations requires continuous application of systemic improvements at the organizational level. Ultimately, violation-free operations should become a natural part of the corporate culture.

1. James REASON (1990). Human error, Cambridge university press, Cambridge, UK.
2. David D WOODS (1994). Behind Human Error: Cognitive Systems, Computers, and Hindsight, CSERIAC State-of-the-Art Report, Wright-Patterson Air Force Base, Ohio, US.
3. Patrick HUDSON (2000). Non-Adherence to Procedures- Distinguishing Errors and Violations.

Want to know more?

Contributors to this page

Authors / Editors

nithin krishnanithin krishna

Other interesting sites
Journal KAI
Wiki of Science
The Balanced Nutrition Index
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License